Many types of equipment require the temporary insertion (and removal) of filters, lenses, detectors, prisms, screens, isolators and other components. The path into which they are inserted and removed may be an acoustic path or an optical, microwave, x-ray or other electro-magnetic (EM) propagation path For convenience of explanation the word “optical” is used herein to represent any and all such acoustic and EM signals and the words “filter” or “filters” are used herein to represent any and all of the components desired to be rapidly inserted and removed from such a path. The most common arrangement in the prior art for temporarily introducing filters is by means of a rotating filter-wheel assembly. A circular array of filters is often provided, rotating around a shaft or pivot to the side of the optical path such that a circle drawn through the centers of the filters passes through the center of the optical path. As the filter-wheel rotates, different filters are introduced into and removed from the optical path. A limitation of this approach is that the filters must be introduced sequentially according to the order in which they have been placed on the filter-wheel. This is a significant limitation where random rather than sequential filter changes are needed.
Another approach used in the prior art is to provide a stack of filters arranged one behind the other off to the side of the optical path. Each filter is coupled to a rotating arm. When actuated the arm flips the filter into or out of the optical path. While this arrangement permits random filter selection it is bulkier and usually heavier than desired because of the need for a separate rotating actuation arm for each filter.
Accordingly, it is desirable to provide an improved filter insertion means and method that overcomes some or all of the limitations of the prior art. In particular, it is desirable that the filter transport apparatus be simple, rugged and reliable, not require rotating wheels or arms and the like for insertion and removal, and be able to provide random filter selection. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.